They provide power to a plethora of portable devices like TV remotes, smartphones, wireless keyboards, smartwatches, clocks, and so much more. 

While having one universal battery available for all applications might save a lot of hassle in choosing the right one, the world of batteries is filled with many different types. 

Batteries can differ in certain characteristics which include; chemical composition, voltage, physical dimension, specific energy, specific power, performance and lifespan. 

Due to this, one type of battery might be more suitable for a particular application compared to another. 

Can you replace NiMH batteries with Lithium?

Yes, you can replace a NiMH battery with a lithium battery. To replace NiMH batteries with lithium, you will need to ensure they are the same size, shape and voltage rating. However, practically it is not a good idea as each battery is designed for different applications. A NiMH battery is more suited for applications requiring high current draw (like power tools) compared to Lithium batteries. 

This article will take a closer look at each battery, as well the key characteristics of batteries and why replacing a NiMH and Lithium battery isn’t really ideal. 

Key characteristics of rechargeable batteries

While some characteristics of a battery might be distinguishable by just looking at them (things like their shape and size), there are other key characteristics which you won’t be able to find out by looks alone. 

These characteristics ultimately determine what type of applications the battery will be used in, as every application has different needs and demands. 

The key characteristics of batteries include; 

• Nominal Voltage
• Specific Energy
• Specific Power 
• Performance 
• Lifespan 

Nominal Voltage

Is the normal voltage that the battery provides. Some batteries might indicate a higher voltage at full charge, however, this voltage drops down to its nominal voltage soon after. 

Specific energy

This is basically the current capacity of a battery which relates to how much current a battery is capable of storing for its given weight. 

If a device needs to operate for long periods of time at a moderate load, batteries with higher specific energy are the ideal choice.

Specific Power

Is the battery’s ability to provide high current. The higher the specific power, the larger the current it can output. 

If a device needs a  high current for a short amount of time, batteries with higher specific power are the ideal choice. The tradeoff is that the specific energy of the battery decreases. 

Performance

A battery is going to be subject to a wide range of temperatures. The performance of a battery gives an indication of how well it will perform to these different temperatures. 

Extreme heat can reduce the lifespan of a battery, while extreme cold can temporarily lower its performance. 

Lifespan

This tells us how long a battery is going to last. Things like temperature, depth of charge and load play huge roles in determining the lifespan. 

As we saw above, heat can drastically reduce the lifespan of a battery. 

Deeper look at NiMH and Lithium batteries

To better understand the question at hand, it will help to learn a bit about both batteries.

NiMH batteries

Let’s start with NiMH batteries. 

The battery is available as disposable (can only be used once), or as a rechargeable (which means they can be used multiple times as long as it is recharged ).

Most of the time (if not all), batteries get their name from what chemical they are composed of. In this instance the chemical composition is Nickel Metal Hydride (where NiMH is just an abbreviation). 

Different types of NiMH Batteries

NiMH batteries are available in various different sizes for different types of devices. While their size varies, the majority of them provide a nominal voltage of 1.2 volts. 

However the size of the battery will affect its current capacity. The smaller the battery, the lower the current capacity, and vice versa. 

Below is a list of the different sizes of NiMH batteries (which are split into two categories; consumer and industrial). They are available with or without tabs.

Consumer;

• AA
• AAA
• C
• D
• 9 volt (rectangular)

Industrial;

• Sub C
• A
• 1/3 AA
• 1/3 AAA
• 2/3 A
• 2/3 AA
• 2/3 AAA
• 4/3 A
• 4/5 A
• 1/2 D

Electronic devices that use NiMH batteries

Due to their ability to deliver high current (specific power), NiMH batteries are used in high drain electronic devices that require this large current to operate.

A digital camera is an example of a device that requires a high current around 1000mA (mainly for the flash). NiMH batteries are able to deliver this current without losing too much of its capacity. 

Other electronic devices that use NiMH batteries include;

• Flashlights 
• Portable Vacuum Cleaner
• Portable power tools (drills, jigsaws, circular saws, sanders, grinders, etc)
• Electric toothbrushes
• Electric razors
• Camcorders

Lithium batteries

Next up are Lithium batteries. 

The most common of lithium batteries used in portable electronic devices is the Lithium Ion. So, going forward this type of Lithium battery will be used. 

Just like the NiMH battery, the lithium ion battery is aptly named due to it using lithium ions. 

During the discharge cycle, the lithium ions move from the negative terminal (cathode), through an electrolyte to the positive terminal (anode).

Different types of Lithium Ion Batteries

Lithium Ion batteries come in a variety of shapes for different applications. 

• Small cylindrical (single cell with, solid body, with no terminals)
• Large cylindrical (single cell,solid body, with threaded terminals)
• Flat or pouch (soft, flat body)
• Rigid plastic case (large threaded terminals) 
• AA
• AAA
• 9V (rectangular) 

Electronic devices that use Lithium batteries

Lithium batteries have a much lower specific power rating compared to NiMH batteries. But, this reduction in specific power results in higher specific energy which means they can provide current for longer periods of time.

This is ideal for devices that do not require high currents, but need to operate for longer periods of time.

Devices such as;

• Smartphones
• Smartwatches 
• Wireless keyboard/mouse
• Wireless speakers
• Wireless earphone/headphones
• Vaping devices 
• Electronic toys 

Can you replace NiMH batteries with Lithium?

Now that we have learnt about some of the crucial characteristics, as well as a little about each battery, we can delve into whether we can replace a NiMH with a Lithium battery.

All batteries have the same task, which is providing power to electrical and electronic devices. But, as we saw there a set of characteristics that ultimately determine the ideal application where a battery will be used.

NiMH have higher specific power, making them ideal for applications that require a large hit of current for short periods of time. 

Lithium batteries on the other hand have higher specific energy, which is perfect for devices that require less current, but need to last for longer. 

At the beginning of the article we saw that you might be able to replace a NiMH with a Lithium battery, however this is not the best idea. 

But why?

This comes down to the specific power and energy of each battery. 

Say you have a portable vacuum cleaner. The vacuum cleaner requires a high current to run the motor to suck dirt on the ground.

A NiMH battery is best suited for a vacuum cleaner as it can provide this high current. 

Now, if we replace this NiMH battery with a Lithium counterpart, the lithium battery is not going to be able to provide the sufficient current to run the motor of the vacuum cleaner.

But, there are many high current devices that use Lithium batteries. How is this possible?

These batteries are designed specifically for certain applications and are not your typical consumer batteries that can be bought off the shelf at your local electronic store. 

They are designed to have high specific energy and power. 

For example, electric cars require high current for the motors, and need to last a long time as well (otherwise you won’t be able to get very far).

What’s the best option if you need to replace the NiMH batteries?

If you need to replace a NiMH battery, your best option is replacing it with another NiMH battery of the same specification (voltage and current capacity).

This way the performance of the device it is being used in will not be affected.

The post Can you replace NiMH batteries with Lithium? appeared first on Electronic Guidebook.

It serves many purposes for a range of applications that include Energy Storage, Power conditioning, Power Factor Correction, Signal Coupling, Decoupling and much more.

There isn’t one specific type of capacitor that is used for any given circuit. They come in a variety of sizes, shapes, voltage ratings, and capacitances. 

Another characteristic that separates capacitors is whether they are Polarized or Non-Polarized. 

Both of which have their unique purposes in different applications mentioned above. 

So, can you replace a polarized capacitor with a non-polarized one?

Yes, you can replace a polarized capacitor with a non-polarized one. However, you will have to ensure that the non-polarized capacitor’s capacitance and voltage ratings are the same (or is higher) than the capacitance and voltage ratings of the polarized capacitor you are replacing. There are some other factors to consider when replacing a polarized capacitor with a non-polarized one which shall be looked at in more detail in this article. 

Difference between a polarized and non-polarized capacitor

To better understand whether a non-polarized capacitor can be used in place of a polarized one it will help to learn the difference between both types of capacitor.

The major difference that separates them is their Polarity. 

Polarity is a term commonly found in the field of electricity. 

There are two poles associated with polarity; Positive (+) and Negative (-).

In a circuit Electrons flow from the negative to a positive pole. 

Many electrical and electronic components are constructed so that they have a polarity. What this means is that one of their terminals will be positive (+) and the other negative (-). 

Common polarized electronic components include batteries, Light Emitting Diodes, IC’s etc.

Polarized components need to be connected to a circuit the right way (their poles need to be matched with the poles of the power source). 

Components with no polarity can be connected to a circuit in no particular orientation. 

But, why create capacitors that are polarized and non-polarized? 

The main reason is that each has its own purpose in different applications. 

Applications of polarized capacitors

Polarization in capacitors is due to the way they are constructed (mainly through the oxide forming process). 

It is constructed in a way to reduce the size of the capacitor while achieving large capacitances.

Polarized capacitors are commonly the go to for low frequency applications as you need capacitors with larger capacitances to do so. 

They also achieve high levels of capacitance within a smaller package.

They are also only used in DC (Direct Current) applications as they cannot be subject to negative voltages associated with AC (Alternating Current) applications.

Common applications of polarized capacitors include;

• Low frequency coupling/decoupling
• Energy storage
• Filtering in power supplies

Applications of non-polarized capacitors

The construction of non-polarized capacitors results in them having no polarity. 

However, this means that non-polarized capacitors tend to be bigger in physical size to achieve the same capacitance of a smaller polarized capacitor. 

But, they have other features that polarized capacitors do not have. 

Non-polarized capacitors consume less power, operate at higher frequencies and work with both DC and AC (as reverse voltages do not affect them). 

Below are some of the most common applications of non-polarized capacitors;

• Coupling
• Decoupling
• Feedback
• Compensation
• Oscillation

When it’s possible to replace a polarized capacitor with a non-polarized one?

As we just saw, each type of capacitor has its own features which means that one might be more suitable for one application compared to the other. 

For example, a polarized capacitor would be a better option in low frequency application as opposed to a non-polarized capacitor.

So, replacing a polarized capacitor with a non-polarized one really comes down to what circuit it will be used in and whether the polarized capacitor was picked for a specific reason.

The main reason would be for its low frequency capabilities.

In this scenario replacing a polarized capacitor with a non-polarized one would not be ideal (as non-polarized capacitors are better suited for high frequency applications).

Also, do not use non-polarized capacitors in power filtering applications as they will cause problems. 

If the parameters of the capacitor, such as frequency do not influence the overall functionality of the circuit, you can replace a polarized capacitor with a non-polarized one (as it can be used in both AC and DC circuits).

Factors to consider when replacing a polarized capacitor with a non-polarized one

If you are using a non-polarized capacitor to replace a polarized one, there are some things to consider before doing so. 

Capacitor ratings

Like every other electrical and electronic device and component, a capacitor has ratings that determine the maximum values that they can operate under before failure. 

Voltage

Voltage is a rating common with every component and device. 

It determines the maximum voltage that can be applied across a capacitor. 

Exceeding a capacitor’s maximum voltage will result in failure (and sometimes in an explosion). 

So, if you are replacing a polarized capacitor with a non-polarized one, ensure that the voltage of the non-polarized capacitor matches (or is higher) than that of the polarized capacitor.

Capacitance

Another important characteristic of a capacitor is it’s Capacitance.

Capacitance is how much total electric charge a capacitor can store.

A capacitor with a certain capacitance value will be chosen for a particular reason in a circuit.

So, make sure the non-polarized capacitor has the same capacitance (or a bit higher) than the polarized capacitor. 

How can you tell if a capacitor is polarized or non-polarized?

Since polarized capacitors can only be placed a certain way in a circuit, it helps to know which terminal is positive and which is negative. 

Otherwise you will be playing the guessing game which is not ideal. 

So, how do you tell if a capacitor is polarized or not?

Lucky for you and me, polarized capacitors have labels on their packaging denoting which lead is positive and which is negative. 

The label will run along the side closest to the lead where (+) is for positive and (-) is for negative.

Can you replace a non-polarized capacitor with a polarized one?

When it comes to replacing a non-polarized capacitor with a polarized one, you will need to take the same factors into considerations mentioned above.

Like was the capacitor chosen specifically for that application for its high frequency capabilities.

If not chosen for specific reasons, you can replace a non-polarized capacitor with a polarized one.

Make sure to match voltage and capacitance values.

But, you cannot use a polarized capacitor in place of a non-polarized one in AC applications (or applications where negative voltages are present). Doing so will cause the capacitor to fail in epic circumstances (explosion!).

Make sure to analyse your circuit to ensure that no negative or reverse voltages are present.

The post Can you replace a polarized capacitor with a non-polarized? appeared first on Electronic Guidebook.

It is also one of the most commonly used microcontrollers used by hobbyists and engineers and found in many electronic devices.

But, can you replace an Atmega8 with an Atmega328? Yes you can replace an Atmega8 with an Atmega328 as both microcontrollers have the same number of pins (28) and have the same operating voltages (2.7 – 5.5 volts). The Atmega8 and Atmega328 also share an almost identical set of peripherals such as the Timers, Analog to Digital Converter, and Serial Communication.

There are some slight differences however, between these two microcontrollers that might see you choosing the Atmega328 over the Atmega8. 

I will highlight these differences later in this article. 

Your reason to want to replace your existing Atmega8 with an Atmega328 could be as simple as you only have an Atmega328 lying around.

No matter what rest assured you can replace them with no problems.

Are the Atmega8 and Atmega328 part of the same microcontroller family?

In the world of microcontrollers, you have many options at your disposal.

There are many manufacturers of microcontrollers which include Atmel, Intel, Texas Instruments, National Semiconductor and Microchip.

These companies are responsible for manufacturing the majority of microcontrollers used today.

These include :

• AVR
• MSP
• PIC
• ARM
• 8051

Among these set of microcontrollers, the AVR family is the most widely used because of its low prices, availability, community and ease of use.

They were produced by Atmel who were acquired later by Microchip.

AVR is the type of architecture that these microcontrollers are built on.

The AVR family is further divided into a subset of families:

• tinyAVR
• megaAVR
• XMEGA

The Atmega8 and Atmega328 are both produced by Microchip, and are part of the megaAVR family.

Reasons you would want to replace your Atmega8 with an Atmega328

You might have been using an Atmega8 for a long time now and want to make the switch to a new microcontroller or you only have a spare Atmega328 lying around.

No matter what your reason ,the Atmega328 is a great choice as it shares many similar attributes as the Atmega8 and can be used as a direct replacement. 

It shares the same number of pins, clock speed, operating voltage, and set of peripherals.

But, there are some very slight differences that might make you want to choose the Atmega328 over the Atmega8 depending on your needs.

Reason #1: Extra PWM channels 

Pulse width Modulation (PWM) is used for many control applications that include controlling DC motors, control valves, pumps, hydraulics and other mechanical parts.

It is also used in applications to control the brightness of lights like LED’s.

Both the Atmega8 and Atmega328 have PWM channels, however, the Atmega328 has three extra PWM channels.

But, do you really need 3 more PWM channels?

Yes!  

Having extra PWM channels is definitely an advantage. The more the better.

Say your next project is robot arm, where you need to control 4 or more servos.

If you opt for the Atmega8 you only have access to three PWM channels and are limited by how many servos you can control.

Instead if your choice is the Atmega328, you have access to six PWM channels which means you will be able to add more servos giving your robot arm more movement. 

Reason #2: Memory

All microcontrollers come with in-built memory. This is the one of the many things that differentiates them from Microprocessors. 

Just like us humans rely on memory for many aspects of life, a microcontroller relies on its memory for many different facets of its operations.

It uses memory to store things that include the program, runtime constants and variables, and other important data.

A microcontroller has three main types of memory:

• Flash Memory
• Static Random Access Memory (SRAM) 
• Electrically Erasable Programmable Read Only Memory (EEPROM)

Flash Memory

This type of memory is ‘non-volatile’, which means when the power is removed from the microcontroller all data stored in Flash memory is saved and not lost.

The program that tells the microcontroller what to do is stored in Flash memory.

Static Random Access Memory (SRAM)

SRAM is a memory which is ‘volatile’.

So unlike Flash memory, when power is removed from the microcontroller, all data stored in SRAM is lost.

Variables and constants which are generated during program runtime are stored in SRAM.

Electrically Erasable Programmable Read Only Memory (EEPROM)

The last type of memory is EEPROM.

EEPROM is ‘non-volatile’ memory. 

It is used to store permanent data which can be called upon later.

Permanent data like device parameters and sensor data. 

Below is a table showing how much memory (Flash, EEPROM, SRAM) the Atmega328 has compared to the Atmega8:

As you can see, the Atmega328 beats the Atmega8 when it comes to memory space for all three types of memory. 

Having more memory is a definite advantage for many different applications as it will allow you to write bigger programs, store more data, and have more runtime constants and variables.

Reason #3: Extra Sleep Mode

While this is not a major difference, it is a difference nonetheless.

Every microcontroller has the ability to enter modes to help save power.

These are known as ‘Sleep Modes’. 

Atmega8 Sleep Modes:

• Idle
• ADC Noise Reduction
• Power-Save
• Power-Down
• Standby

Atmega328 Sleep Modes:

• Idle
• ADC Noise Reduction
• Power-Save 
• Power-Down
• Standy
• Extended Standby

The Atmega328 has one more sleep mode than the Atmega8. 

Having one more sleep might not seem like a big deal, but it gives you more options for conserving power which can be vital in prolonging battery life.

Reason #4: Price

The last difference between an Atmega328 and Atmega8 is their prices.

The prices shown below are as shown on Microchips website.

Again the Atmega328 comes away as the winner when it comes to price.

You might think that the price difference is negligible. You are only saving $0.37.

But, think about if you buy 100 Atmega328’s compared to 100 Atmega8’s.

You will be making a saving of $37 in the long run!

Can I use the same programmer and IDE to program an Atmega8 or Atmega328?

Now you know that you can replace the Atmega8 with the Atmega328, you will need a way to write code and program it. 

The great news is that, because both these microcontrollers are manufactured by the same company and are part of the same family, they can be programmed using the same programmer and Integrated Development Environment (IDE).

A list of IDE’s that you can use program the Atmega328 include

• Codevision AVR
• Atmel Studio
• WinAVR
• AVR-GCC

A list of AVR programmers you can use to burn the code onto the Atmega328 are:

• AVRISP
• AVR Dragon
• STK500
• JTAG Programmer/Debugger

Other microcontrollers that can replace an Atmega8?

When it comes to options for replacing the Atmega8, you have many choices available.

The Atmega328 isn’t the only microcontroller that is available at your disposal.

The table below is taken from the Microchip website and lists all the microcontrollers you can use to replace an Atmega8. 

The list of microcontrollers below are all capable of replacing the Atmega8. This list is taken from the Microchip website. 

• Atmega168
• Atmega168A
• Atmega168P
• Atmega168PA
• Atmega168PB
• Atmega328
• Atmega328P
• Atmega328PB
• Atmega48
• Atmega48A
• Atmega48P
• Atmega48PA
• Atmega48PB
• Atmega88
• Atmega88A
• Atmega88P
• Atmega88PA
• Atmega88PB
• Atmega8A

Final thoughts

You might be currently using the Atmega8 and wanting to make a switch to a different microcontroller, or your Atmega8 has stopped working and the only other microcontroller you have is the Atmega328.

No matter what your purpose is to replace the Atmega8 with an Atmega328, rest assured you can do so with no hindrance.

Both are interchangeable as they come from the same family of microcontrollers.

They both have the same number of pins, operate at the same voltages, and can be programmed using the same programmer in the same Integrated Development Environment.

The post Can I replace an Atmega8 with an Atmega328? appeared first on Electronic Guidebook.